1. Field of the Invention
The invention relates generally to spraying mechanisms which may be detachably connected to a container for spraying the contents thereof. More particularly, the invention relates to manually activated spray heads.
2. Description of the Prior Art
Manually activated spray heads are well known for spraying products such as window cleaners, all-purpose cleaners, hair sprays, etc. Most of such prior art spray heads are either of the piston or the bulb type.
In the piston type spray head, a manual trigger mechanism forces a piston to expel a predetermined volume of fluid from the nozzle. An arrangement of tubes and check valves enables the spray head to move fluid in a predetermined direction during operation of the trigger mechanism (i.e. only from container to nozzle and not back). In a bulb-type spray head, a manual trigger mechanism is used to squeeze a predetermined amount of fluid from a bulb. An arrangement of tubes and valves is also utilized to enable fluid flow only in a predetermined direction.
One other type of liquid spray head (disclosed in U.S. Pat. No. 4,232,828) utilizes a removable liquid conduit in combination with a star-shaped rotor rotatably driven by a manual trigger mechanism. Activation of the trigger causes the star-shaped rotor to compress the liquid conduit in an undulating manner and force liquid therefrom to the spray head nozzle.
All of the foregoing prior art spray head mechanisms suffer from various disadvantages. They are all generally complex and require the assembly of many different parts. Those spray heads utilizing flexible components (bulbs, conduits, etc.) have a tendency to deteriorate over time. The check-valves incorporated in these various mechanisms either lose resiliency or get clogged with the product being sprayed. Furthermore, none of the prior art spray heads may be easily adjusted to deliver product at a variable rate. That is, once a predetermined spray head is designed with certain dimensions, it will deliver a predetermined quantity of product at a predetermined rate. Changing either the desired volume or rate requires redesign of substantially the entire unit.
Gear pump spray heads are known in the prior art for spraying container contents such as paint, etc. Gear pumps may generally avoid check-valves and other disadvantages of prior art spray heads and are shown in U.S. Pat. Nos. 2,651,545 and 3,993,250. However, both of these devices require continuously rotating electrically or battery operated drive motors. Consequently, these devices are too complex and costly for many applications. The continuous drive feature also makes such spray heads unsuitable for many applications where an intermittent spray operation is acceptable or desirable from either a cost or efficiency point of view.
To overcome the disadvantages of the prior art, it is an object of this invention to produce a manually operated spray head requiring fewer parts than prior art piston or bulb-type spray heads. It is a further object of this invention to provide a manually operated spray head which is operable without the need for check valves. It is yet another object of this invention to provide a manually operated spray head which may be easily and inexpensively assembled. It is still a further object of this invention to provide a manually operated spray head design which may be relatively easily adjusted to vary the delivery rate of the spray head.